Unsaturated fatty acids are hydrocarbons in which one of the hydrogen atoms has been replaced by a carboxyl group (COOH) and which contain one or more double bonds between carbon atoms. These acids, particularly essential fatty acids such as linoleic, linolenic and arachidonic acids, play an important role in nutrition. Unsaturated fatty acids are derived commercially from vegetable, animal, and marine sources, particularly fish oils, by conventional solvent extraction methods. The solvents used for the extraction, such as benzene, dichloromethane or acetonitrile, are expensive and leave behind an undesirable and, in some cases, poisonous residue. Thus, a safe and inexpensive method which eliminates the aforementioned deficiencies is needed in the art.